Lubricating compositions containing 1, 3, 5-triazine compound and metal salt of fatty acid



United States Patent 3,189,542 LUBRICATING COMPOSITIONS CONTAINING 1,3,5-TRIAZINE COlVlPOUND AND METAL SALT OF FATTY ACID Arnold J. Morway, Clark, and Hans G. Vesterdal, Elizabeth, N.J., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed Mar. 1, 1963, Ser. No. 262,250 7 Claims. (Cl. 252-17) This invention relates to lubricating compositions. More specifically, this invention relates to lubricating oils thickened to a grease consistency with a mixture of 1,3,5- triazine compound and metal salt of C to C fatty acid. These lubricating grease compositions are particularly suited for high temperature lubrication. They will find particular application in prepacked bearings running without a sump.

The trend in the design of modern aircraft has accentuated the need for lubricating compositions and particularly greases which will effectively lubricate anti-friction bearings operating at high rotational speeds and high temperatures. While considerable progress has been made in recent years in producing improved aircraft greases, some difliculty has been encountered in producing a grease which which will effectively lubricate bearings operating at high rotational speeds and high temperatures for prolonged periods of time. Conventional aircraft greases currently available to the consumer have generally failed to meet the requirements placed on such a lubricant.

DISCOVERY It has now been discovered, and this discovery forms the basis of the present invention, that lubricating oils and, in particular, silicone and silane fluids or oils may be advantageously thickened to a grease consistency with a mixture of metal salt of C -C fatty acid and a triazine compound. Lubricating compositions prepared according to the preferred form of the present invention are especially adapted for use over a wide temperature range and are particularly eflicacious in lubricating bearings operating at high rotational speeds, e.-g., 10,000 r.p.m.s, and at temperatures of up to 400 F. for prolonged periods of time. Moreover, these preferred lubricating compositions may be effectively used for shorter periods of time at temperatures up to 650 F. and have excellent anti-wear properties.

The amount of the triazine compound .used as the primary thickener may vary over wide limits depending upon the particular oil with \which the triazine compound is to be blended and upon the properties desired in the final lubricating composition. While as much as 60 percent by weight of the total composition may comprise the triazine compound, it is preferred to use smaller amounts, that is, on the order of about 3 to 55 wt. percent, e.g., 5 to 50 wt. percent based on the total lubricating composition weight. A particularly preferred amount is from about 8 to 30 wt. percent. It should be understood, however, that, depending upon the consistency of the composition desired, less than 3 percent or more than 60 percent of the triazine compound may be employed.

The amount of the combined triazine and metal salt of C to C fatty acid used will be suflicient to thicken the lubricating oil to a grease consistency. In general, this amount comprises about 10 to 70 wt. percent, more usu- 3,189,542 Patented June 15, 1965 "Ice ally from 15 to 65 wt. percent, e.g., 18 to about wt. percent of the total composition. A particularly preferred amount is from about 20 to 40 wt. percent. The weight ratio of the triazine compound to fatty acid salt will vary depending upon the characteristics desired in the ultimate composition. In general, however, the weight ratio of the triazine compound to fatty acid salt will be between about 0.321 and 6:1 or more, more usually this ratio will :be between about 0.511 and 4:1, e.g., from about 0.6:'1 to 2.5:1. A particularly preferred ratio is from about 0.7:1 to 2:1.

SUITABLE TRIAZI'NE COMPOUNDS The triazine compounds which are contemplated for use according to the present invention are derivatives of symmetrical (1,3,5) triazine. It is preferred that the triazine employed have a melting point about 400 F. since service above 400 F. is desired.

The triazine compounds of the present invention are those having the formula:

wherein R and R' are selected from the group consisting of hydrogen, alkyl, aryl, alkaryl, aralkyl, cyanoalkyl, pyridyl, amino, hydroxy and mercapto radicals, R and R being unlike radicals when selected from the group consist ing of amino, hydroxy and mercapto radicals. Thus, the novel lubricating compositions of the present invention comprise a dispersion in a lubricating oil of a mixture of a 1,3,5-triazine melting above about 400 F. and metal salt of C to C fatty acid in a finely divided form.

It will be noted that R and R can be the same or different radicals when selected from the group consisting of hydrogen, alkyl, aryl, alkaryl, aralkyl, cyanoalkyl and pyridyl radicals provided, of course, that the melting point of the compound is at least 400 F. When R and R are selected from the group consisting of amino, hydroxy and mercapto radicals, the radicals should not all be the same. For example, it is not intended to include compounds such as cyanuric acid (s-triazine-triol) or melamine (2,4,6- triamino-s-triazine) because of their thermal insta bili-ty.

An especially preferred group of triazine compounds for the purpose of our invention includes those compounds wherein each of the R radicals is an amino radical (guanamine derivatives). Preferred are those wherein R is selected from the group consisting of hydrogen, alkyl (e.g., methyl, ethyl, propyl and n butyl), aryl (e.g., phenyl and naphthyl), alkaryl (e.g., toly l), aralkyl (e.g., benzyl), cyanoalkyl (e.g., cyanoethyl, cyanobutyl and cyanooc-tyl), pyridyl, hydroxy and mercapto radicals. When R is an alkyl radical, it is preferably selected from the group consist-ing of methyl, ethyl, propyl and n-butyl radicals in order to give a compound having a melting point above about 400 F. When R is an alkaryl or an aralkyl, radical, the alkyl portion of the alkaryl and aralkyl radicals preferably contain not more than 2 carbon atoms. When R in the preferred triazines (i.e., diamino) is a cyanoalkyl radical, the alkyl portion of the cyanoalkyl radical can contain as many as 8 carbon atoms and still give a compound melting above 400 F.

Illustrative of the preferred diamino triazines which can be used in the present invention are the following: 2,4-diamino-1,3,5-triazine 2,4-diamino-6-methyl-1,3,5-triazine 2,4 diamino-6-ethyl-1,3,5-triazine 2,4-diamino-6-propyl-1,3,5-triazine 2,4-diamino-6-n-butyl-1,3,5-triazine 2,4-diamino-6-phenyl-1,3,5-triazine 2,4-diamino-6-a-naphthyl-1,3,5-triazine 2,4-diamino-6- 8-naphthyl-1,3,5-triazine 2,4-diamino-6-m-tolyl-1 ,3 ,5 -tri azine 2,4-diamino-6-p-tolyl-1,3,5-triazine 2,4-diamino-6-benzyl-1,3,5-triazine 2,4-diamino-6-cyanoethyl-1,3,5-triazine 2,4-diamino-6-cyanobutyl-1,3,5-triazine 2,4-diamino-6-cyanooctyl-1,3,S-triazine 2,4-diamino-6-pyridyl-l,3,5-triazine 2,4-diamino-6-hydroxy-1,3,5-triazine 2,4-diamino-6-mercapto-l,3,5-triazine While these preferred diamino triazines are all elfective thickeners for the preparation of high temperature greases (in this respect see US. No. 2,984,624, which is incorporated herein by reference), it is not to be implied that all serve with equal etficiency, since the various compounds may vary to some extent depending upon the nature and severity of the service to which they are subjected. Those diamino compounds which contain an aryl radical such as a phenyl radical are sometimes preferred because of the increased thermal stability contributed to the compounds by such a radical. For many commercial applications, 2,4-diamino-6-hydroxy-1,3,5-triazine is the most preferred.

The 1,3,5-triazine compounds of the present invention can be prepared according to known chemical procedures. Neither the compounds, per se, nor their preparation constitutes any portion of the present invention.

SUITABLE FATTY ACIDS AND SALTS THEREOF Suitable fatty acids include the C to C fatty acids, e.g., formic acid, acetic acid, propionic acid, n-butanoic acid, n-hexanoic acid, etc. These acids will be present in the form of their alkali metal or alkaline earth metal salts, e.g., Na, Ii, Sr, Ba, Ca, etc. All of these metals do not serve with equal efficiency, however. For example, the magnesium salts are more diflicult to suspend in oils than are the calcium salts. The alkaline earth metal salts are preferred and the calcium salts are the most preferred. Of the fatty acids, acetic acid is the preferred acid. These fatty acid salts do not, per se, form stable dispersions in lubricating oils, but rather settle out rather rapidly.

The prior art (US. No. 2,984,624) has shown that high temperature greases may be made by combining triazine compounds with organophilic siliceous materials which are thickeners in their own right. It was, therefore, surprising to discover that many of the desirable properties of the prior art compositions could be retained and the extreme pressure and anti-wear properties improved by eliminating the secondary thickener (the organophilic material) and replacing it with a non-thickening agent, i.e., fatty acid salt.

When other materials, e.g., lead noble, phosphates, chlorides, sulfur compounds, etc., have been tried as E.P. additives at high temperatures (ca 400 F. and higher) they did not possess the desired anti-wear or E.P. properties. When these compounds were employed, the lubricating lives of the bearings tested were extremely short. Bearing failure was generally due to cage failure.

On the other hand, the fatty acid salts and particularly calcium acetate, retain their load carrying ability and antiwear properties at elevated temperatures. Calcium acetate does not react with metal surfaces to form non-melting salts or compounds. It is non-corrosive and on this basis does not change metal surface clearances (resulting in bearing wear) nor does it wear out. It also appears that the excellent thickening power resulting from the use of triazines and fatty acid salts must stem from some sort of a complex between the two. In this respect, however, the present inventors do not desire to comm1t themselves to any particular explanation.

PREPARATION OF THE FATTY ACID SALTS The ultimate qualities of lubricating compositions prepared according to the present invention are greatly enhanced by reducing the particle size of the fatty acid salt, e.g., calcium acetate, to as small a size as possible. For example, reduction of the particle size of calcium acetate below 5 microns, e.g., less than 2 microns, produces a lubricating grease which is much smoother and has clearly enhanced anti-wearing properties when compared with a similar grease prepared from commercially available calcium acetate having a particle size of from 25 to 200 microns. For purposes of illustration only the preparation of the fatty acid salts will be described with particular reference to calcium acetate.

The in situ preparation may be used. Here the calcium acetate is formed in the oil in the presence of the triazine compound, e.g., ammeline, by adding, for example, hydrated lime to acetic acid. If a slight excess of acid is used in the case of silicone oils, the resulting grease will have an improved lubrication life as contrasted to a similar grease prepared using an excess of base. This apparently stems from the fact that silicone oils are less stable in an alkaline environment. Alternatively, and more preferably, the calcium acetate may be prepared separately and added in a preformed state. A surfactant, e.g., from 0.5 to 5 wt. percent barium dinonyl sulfonate, may be employed to advantage during the addition of preformed calcium acetate to the oil to aid in forming a smooth grease and prevent further agglomeration.

By far the more preferred technique involves the separate preparation of calcium acetate in the presence of a surfactant. The presence of a surfactant seems to coat the particles of calcium acetate as they form, thus preventing agglomeration. A particularly effective technique of this type has been recently developed.

Briefly described, this preferred technique for obtaining the small particle size, e.g., about 0.1 micron, of calcium acetate is as follows: calcium acetate is mixed with water to form a saturated solution, or more preferably a concentrated calcium acetate/water slurry, e.g., containing 35 to wt. percent, of calcium acetate in water. This solution is then added to a small amount of lubricating oil, e.g., mineral lubricating oil, in which is dispersed a surface active agent of the amino imidazoline salt type. This resulting mixture is heated to drive off suflicient water to form an aqueous emulsion, e.g., 50 wt. percent of water based on the total weight of the then existing mixture. The emulsion is then cooled to form an oatmeallike mass, into which is mixed a relatively large amount, e.g., about 4 times the volume of said oatmeal-like mass, of a volatile hydrocarbon solvent such as heptane, etc. Solvents, such as heptane, form a partial azeotrope with water and thus aid in its removal. The solvent also removes water mechanically (entrainment). Heating is initiated and the solvent refluxed while simultaneously drawing off the water (which is heavier than the solvent and can be separated from the solvent by gravity, e.g., a trap on the reflux condenser). When substantially all of the water has been removed, e.g., the water content of the residue is less than 1.0 wt. percent, lubricating oil, e.g., 2 parts of a mineral lubricating oil, is added to the emulsion residue and the solvent, e.g., heptane, removed by distillation. The resulting gel contains finely disphersed calcium acetate crystal needles less than 5 microns in length, e.g., about 0.5 micron in length and 0.1 micron in diameter. Alternatively, and more preferably, after the aqueous emulsion has been reduced to a water content of about 1.0 wt. percent, the resulting heptane dispersion can be reduced to dryness (without adding oil) by distilling both heptane and water from the dispersion. When all of the water has been removed, the heptane, alone, is distilled off. As the heptane/calcium acetate mixture becomes sufficiently concentrated, the coated calcium acetate particles will precipitate. Calcium acetate in the form of a soft-flulfy powder can then be recovered by drying the precipitate.

While not completely understood, it is believed that the acid salt of the imidazoline acts as a crystal growth inhibitor by coating the calcium acetate particles as they form, thus preventing their aggregation into larger particles.

The amino imidazolines used in forming the imidazoline salts of the type just described include those having the general structure:

In the above formula, 12 represents an integer of from about 2 to 6, preferably 2 to 3; R represents a C to C preferably a C to C hydrocarbon group, either saturated or unsaturated, and preferably aliphatic; while R is either hydrogen or a C to C alkyl group. Preferably, R is hydrogen and n is a small integer, e.g., 2., in order that the effectiveness of the imidazoline can be as great as possible per pound of material. In other words, the apparent effectiveness of the imidazoline in the present invention seems to depend on the ring structure and the terminal amino group, while the number of carbon atoms in the branches merely dilutes the apparent effectiveness.

A specific example of an imidazoline of the above formula, which was used in the working examples of the invention, is a commercially available imidazoline, 1-(2 amino ethyl) -2-(n-alkyl)-2-imidazoline having the formula:

wherein R represents heptadecenyl and heptadecadienyl chains in a mole ratio of about 1:1. This product is commercially available under the tradename Nalcamine G-39M and is sold by Nalco Chemical Company, Chicago, Illinois.

The acids, which can be reacted with imidazoline to form the salts, include inorganic mineral acids such as ortho, pyro and meta phosphoric acids, hydrochloric acid, sulfuric acid, nitric acid, and also phytic acid which is closely related to phosphoric acid. Phytic acid is the preferred acid.

Phytic acid is the hexaphosphoric acid ester of inositol. It is a strong acid containing twelve acidic hydrogen groups. Its structural formula is believed to be as follows:

This materials, having a molecular weight of 666 with 12 reactive hydrogen groups, has a combining weight (mole equivalent weight) of 55.

Phytic acid is derived from grain, and is a by-product from waste corn steep liquor. A description of phytic acid and its preparation is given in Chemical Engineering, January 27, 1958, under the title Ion Exchange Now Yields Phytic Acid, published by McGraw-Hill Publishing Co., Inc., New York, New York.

The amino imidazoline salts may be prepared 'by mixing the imidazoline and appropriate acid in mole equivalent ratios of from 5 to 30, e.g., 8 to 20, preferably in a small amount of inert hydrocarbon oil, e.g., 0.5 to 3.0 or more parts by weight per part of combined imidazoline and acid, to form the imidazoline salt. Reaction times will generally be from 0.05 to 1 hour, more usually from 15 to 30 minutes. Temperatures of from 75 to 200 F. are usually employed, although other temperatures may be used. For best results, the relative amounts of imidazoline salt and oil should be sufiicient to form a gel at 77 F.

SUITABLE LUBRICA'FING OIL The lubricating oil in which the triazine compound and calcium acetate are incorporated is preferably a lubricant of the type best suited, per se, for the particular use for which the ultimate lubricating composition is designed. Since many of the properties possessed by lubricating oil are imparted to the ultimate lubricating composition, it is advantageous to employ an oil which is, itself, thermally stable at the contemplated temperature of lubrication. Some mineral lubricating oils, e.g., hydrotreated mineral oils, are sufliciently stable to provide a lubricating base for greases -to be used under moderately elevated temperatures. Where temperatures in the order of 400 F. and above are expected (as contemplated herein), synthetic oils form a preferred class of lubricating bases because of their high thermal stability. 'The term synthetic oil is meant to define an oil of nonamineral origin. The synthetic oil may be an organic ester, e.g., di-Z-ethylhexyl sebacate, etc. Alternatively, polymerized olefins, copolymers, alkylene glycols and alkylene oxides, polyorgano siloxanes, polyphenyl ethers, chlorinated silicones, nitrile s'ilicones, etc., may be used.

The preferred lubricating oils for use according to the present invention include the silicone fluids (polyor-gano siloxanes) and silanes. These silicon-containing fluids are particularly preferred because of their high thermal stability and compatibility with the thickening mixture of the present invention. The silanes can be represented by the general formula:

wherein R represents an alkyl group, e.g., C -C or an aryl group such as phenyl, naphthyl, biphenyl, etc. or C to C substituted aryl groups. The Rs may be the same or dilferent. Examples of such oils include heptyl trip'henyl silane, diheptyl diphenyl silane, dinonyl dinaphthyl silane, etc. A silane of particular import is a dilauryl diphenyl silane that is commercially available from the Dow Corning Corporation of Midland, Michigan, under the trade designation QF-6-7009. The characteristics of that silane are shown in Table I.

7. Even more preferred as the lubricating oil base are the silicone fluids. These silicon-containing fluids are polymers made up of recurring units of silicon and oxygen atoms as indicated by the general formula below:

The silicon atoms may be substituted (the R groups) with alkyl, aryl, alkaryl, aralkyl, or cycloalkyl groups. The Rs may be the same or different. The number of these recurring units may vary widely and will be a function of the properties desired, e.g., viscosity, pour point, etc. The substituents will also affect the number of units in a polymer having a fixed viscosity. Examples of such compounds are the dimethyl silicone polymers, diethyl silicone polymers, methylphenyl silicone polymers, ethyl phenyl silicone polymers, etc. Two silicone fluids, both extremely desirable, are commercially available from the Dow Corning Corporation, Midland, Michigan, under the trade designations QF-6-7012 and QF6-7024. They are both poly methyl phenyl siloxanes. The properties of these materials are shown in Table H.

Table II A particularly useful reference to those who are interested is a book entitled Synthetic Lubricants, edited by R. C. Gunderson and A. W. Hart, copyright 1962 by the Reinhold Publishing Corporation. In particular, Chapter 7 is devoted to silicones and has been written by several employees of the Dow Corning Corporation.

If desired, a blend of oils of suitable viscosity may be employed as the lubricating oil base instead of em ploying a single oil. The viscosity of the lubricating oil base or blend of oils will generally range from less than 1 to 500 or more cs. 100 F. and more usually from about to 400 cs., e.g., to 300 cs.

The lubricating compositions prepared according to the .present invention may contain lubricant additives, if desired, to improve specific properties of the lubricant without departing from the scope of the present invention. Thus the lubricating compositions of the present invention may contain corrosion and rust inhibitors, anti-oxidants, dyes, etc. Whether or not such additives are employed and the amounts thereof, depend to a large extent upon the severity of the conditions to which the composition is subject and upon the original stability of the lubricating oil base. For example, poly organo siloxanes are, in general, more stable than mineral lubricating oils and thus require the addition of little, if any, oxidation inhibitors to duplicate the low temperature performance of mineral oils. However, high temperature operations as contemplated herein, of necessity, often require their use. When such conventional additives are used, they are generally added in amounts between about 0.01 and 10 wt. percent based on the weight of the total composition. Preferred anti-oxidants for the silicon-containing greases of this invention include phenyl-wnapht-hylamine; p,p'-diotcyl diphenyl amine and dipyridyl amine.

It has also been found that a mixture of oxidation inhibitors is more efficacious than the same total concentration of a single inhibitor. For example, a mixture of phenyl-a-naphthylamine (3 wt. percent) and p,p-dioctyl diphenyl amine (2 wt. percent) has been shown to be more effective, in terms of high temperature lubricating life, than 5 wt. percent of either inhibitor alone. Usually from 1 to 3 wt. percent of p,p'-dioctyl, diphenyl amine 8 will be used together with from 2 to 5 wt. percent of phenyl-u-naphthylamine. Occasionally, however, it will be desirable to use other amounts, other inhibitors, or none at all.

EXAMPLES The present invntion will be more clearly understood by reference to the following specific examples which include a preferred embodiment. Unless otherwise indicated, all parts are by weight.

EXAMPLE 1 A test control grease (containing no fatty acid salt) was prepared as follows for comparative purposes. Forty parts of 2,4-diamino-6-hydroxy1,3,5-triazine was added to 60 parts of a poly organo siloxane (Dow Corning QF- 6-7012) and heated with stirring to 250 F. After maintaining the mixture at that point for 4 hours to obtain the desired structure and dispersion, it was cooled to 110 F. and milled in a Morehouse mill having a clearance of 0.001 inch. The formulation and properties of the resulting grease are shown in Table IH.

EXAMPLE 2 Fifty parts of 2,4-diamino-6-hydroxy-1,3,5-triaziue were added to, and intimately mixed with, a silicone fluid (QF- 6-7012). The resulting mixture was heated to 300 F. Three parts of phenyl-a-naphthylamine and 2 parts of p,p'-dioctyl diphenyl amine were added and the-resulting composition was cooled to about 110 F. and milled in a Morehouse mill. The formulation and properties of the resulting grease are shown in Table III.

EXAMPLE 3 Thirty parts of 2,4-diamino-6-hydroxy-1,3,5-triazine and 20 parts of calcium acetate (half-hydrate) were added to 45 parts of a silicone fluid (QF-67012) and heated, with mixing, to 350 F. The calcium acetate employed was prepared by the imidazoline phytate method and had a particle size of 0.1 x 0.8 micron (needle-like). The mixture was cooled to 300 F. where 2 parts of p,p'-dioctyl diphenyl amine and 3 parts of phenyl-u-naphthylamine were added with mixing. The mixture was then cooled to 110 F. and milled. The formulation and properties of the resulting grease are shown in Table III.

EXAMPLE 4 12.50 parts of calcium acetate (anhydrous) and 46 parts of 2,4-diamino-6-hydroxy-1,3,5-triazine were intimately mixed with 37.59 parts of a silicone fluid (QF-670l2) and heated to 350 F. The calcium acetate was prepared by passing coarse calcium acetate particles at high speed around a toroidal path until the particle size had been reduced to 0.5 to 2.0 microns by attrition. The mixture was then cooled to 200 F. where 1.56 parts of p,p'- dioctyl diphenyl amine and 2.35 parts of phenyl-u-naphthylamine were added. The resulting composition was then cooled to 100 F. and milled. The formulation and plrloperties of the resulting grease are shown in Table EXAMPLE 5 Twenty-five parts of 2,4-diamino-6-hydroxy-1,3,5-t1'iazine and 25 parts of calcium acetate (half-hydrate) were intimately mixed with 43 parts of a silicone fluid (QF-6 7012) and 2 parts of a 50 wt. percent solution of barium dinonyl naphthalene sulfonate in a mineral lubricating oil having a viscosity at 100 F. of SUS. The calcium acetate had a particle size of 0.1 x 0.8 micron and was produced by the imidazoline phytate technique. The mixture was then heated to 300 F. Two parts of p,p'- dioctyl diphenyl amine and 3 parts of phenyl-a-naphthylamine were then added and the resulting composition cooled to F. and milled. The formulation and properties of the resulting grease are shown in Table III.

EXAMPLE 6 Twenty-five parts of 2,4-diamino-6-hydroxy-1,3,5-triazine and 35 parts of a calcium acetate (anhydrous) sub- 9 stantially as described with reference to Example 4 were intimately mixed with 35 parts of a silicone fluid (QF-- 7012) and heated to 300 F. Two parts of p,p'-dioctyl diphenyl amine and 3 parts of phenyl-a-naphthylamine were then added and the resulting composition cooled to 110 F. and milled. The formulation and properties of the resulting grease are shown in Table III.

EXAMPLE 7 Twelve parts of 2,4-diamino-6-hydroxy-1,3,5-triazine and 12 parts of a preformed coated calcium acetate (imidazoline phytate preparation having a particle size of about 0.1 x 0.8 micron) were intimately mixed (in reverse order) with 75 parts of a silicone fluid (QF-6-7012) and milled. The mixture was then heated to 320 F., 1 part of phenyl-a-naphthylamine was added, the mixture cooled and then remilled. The approximate formulation and properties of the resulting grease are shown in Table III.

The finely divided calcium acetate particles used in Examples 3, 5, and 7 were formed as follows: 17.2 parts of a mineral lubricating oil having a viscosity of 55 SUS at 210 F. and 10.0 parts of an alkylated imidazoline (Nalcamine G-39M) were mixed together. The imidazoline was then neutralized with 2.2 parts of phytic acid thereby forming a gel. To this gel were added 70 parts of calcium acetate in the form of a saturated aqueous solution. Heating was initiated and enough water was removed to form a stable gel. Approximately 4 volumes (based on the volume of the gel) of heptane was added to the gel and the mixture distilled in a distillation flask equipped with a reflux condenser and trap. Water that had been distilled was withdrawn from the trap and the heptane was returned to the product in the flask. As the product in the flask became sufliciently concentrated (dry), calcium acetate particles precipitated. These particles were collected and then dried in an oven at 125 P. On inspection they appeared as small needle-like particles about 0.1 micron in diameter and about 0.8 micron in length.

ties. The same is true of Example 4 which was an excellent grease and was somewhat more firm. The grease of Example 5 was also a good performing grease. The presence of the sulfonate seemed to appreciably aid in producing a smoother grease than previously prepared. The grease of Example 6 was somewhat grainy, but still performed well. The grainy quality of that grease can be enhanced by the addition of a sulfonate (see Example 5). Again, the grease of Example 7 performed quite well and was still effective after 1,000 hours at 400 F. and 10,000 r.p.m.

Thus it can be seen that a triazine, alone produces a generally unsatisfactory grease. The addition of calcium acetate improves its BF. and anti-wear properties; the addition of a sulfonate improves its smoothness; and the addition of oxidation inhibitors improves its lubrication life. The net result is the transformation of a mediocre product into an efiicacious high temperature lubricant.

While the present invention has been described with a certain degree of particularity, it should be realized the numerous modifications and adaptations can be made within the spirit and scope of the invention as hereinafter claimed.

We claim:

1. A solid lubricating grease consisting essentially of (a) a major proportion of a polyorgano siloxane having a viscosity at 100 F. of from 10 to 300 cs., (b) about to 40 wt. percent of a mixture of 2,4-diamino-6-hydroxy- 1,3,5-triazine and calcium acetate in a weight ratio of from 0.7 :1 to 2:1, said calcium acetate having a particle size of less than about 2 microns, (c) from 1 to 3 wt. percent of p,p'-dioctyl diphenylamine, and (d) from 2 to 5 Wt. percent of phenyl-a-naphthylamine.

2. A lubricating grease composition consisting essentially of: (a) a polyorgano siloxane lubricating oil, and (b) from 18 to about 60 wt. percent of a mixture of guanamine compound and calcium acetate in a weight ratio of from 0.521 to 4:1, (c) said guanamine com- Table III Examples Formulation Triazine 40 50 46 25 25 12 Calcium acetate 20 12. 5 25 12 Silicone Fluid 60 45 37. 49 43 35 75 Phenyl-q-naphthylamine 3 3 2. 35 3 3 1 p,p'-Dioctyl diphcnyl amine 2 2 1. 56 2 2 Barium dinonyl naphthalene sull'ouate solution. 2

PRorEBrms Appearance Excellent Excellent Excellent Excellent Excellent Grainy Excellent Smooth Smooth Smooth Smooth Smooth Smooth Dropping point, F 500+ 500+ 500+ 500+ 500+ 500+ 500+ ASTM penetration (mm.l10);

Unworked 387 315 348 221 317 245 295 Worked 60 X 384 323 356 218 328 257 310 ABEC-lVL GISpi.udle life (hours at 10,000

450 F 42 234 348 265 265 1, 025 4-bal1 wear test 1 (scar dia., mm.) 1. 52 0. 74 0.84 0. 0.72 0. 40 Triazine/Ca acetate, weight ratio 1. 5 3. 8 1.0 0. 7 1. 0 Almen test (weights) 2 15 1 Steel on steel, 10 kg, 1 hour, 75 0., 1800 r.p.n1. 2 Gradual and shock.

It can be seen from Table III that the lubricating grease of Example 1 which contained no calcium acetate, no inhibitors and no sulfonates had a very poor lubrication life at 450 F. (only 42 hours). The addition of a mixed inhibitor package (Example 2) resulted in a grease having a considerably longer lubrication life (234 hours) but had very poor wear characteristics (1.52 mm. scar diameter). The grease of Example 3 was very excellent. It had a long lubrication life and much better wear properpound melting above 400 F. and having the general formula:

wherein R is selected from the group consisting of hydrogen, alkyl, aryl, alkaryl, aralkyl, cyanoalkyl, pyridyl, hydroxy and mercapto radicals and wherein the alkyl radical contains from 1 to 4 carbon atoms and wherein the alkyl portion of the alkaryl and aralkyl radicals contain from 1 to 2 carbon atoms and wherein the alkyl portion of the cyanoalkyl radical contains from 1 to 8 carbon atoms, and (d) said calcium acetate being formed in the pres ence of an amino imidazoline salt, aid amino imidazoline salt being the reaction product of an amino irnidazoline and an acid selected from the group consisting of inorganic mineral acids and phytic acid, said amino imidazoline having the general formula:

wherein n is an integer of about 2 to 6, R is a C to C hydrocarbon group and R is selected from the group consisting of hydrogen and C to C alkyl groups.

3. A lubricating grease composition as defined in claim 2 wherein said guanamine compound is 2,4-diamino-6- hydroxy-1,3,5-triazine.

4. A lubricating grease composition as defined in claim 3 which also contains from 0.5 to 5 Wt. percent of barium dinonyl naphthalene sulfonate.

5. A lubricating grease composition as defined in claim 3 which also contains from 2 to 5 vvt. percent of phenyl u-naphthylamine.

6. A lubricating grease composition consisting essentially of: (a) a polyorgano s-iloxane lubricating oil, and (b) from 15 to 65 wt. percent of a mixture of alkaline earth metal salt of C to C fatty acid and a guanamine compound, (c) said guanamine compound melting above aboue 400 F. and having the general formula:

wherein R is selected from the group consisting of hydrogen, alkyl, aryl, alkaryl, aralkyl, cyanoalkyl, pyridyl, hydroxy and mercapto radicals and wherein the alkyl radical contains from 1 to 4 carbon atoms and wherein the alkyl portion of the alkaryl and aralkyl radicals contain from 1 to 2 carbon atoms and wherein the alkyl portion of the cyano alkyl radical contains from 1 to 8 carbon atoms, and (d) said mixture consisting of said guanamine compound and fatty acid salt in a weight ratio of from 0.5:1 to 4:1.

'7. A lubricating grease composition consisting essentially of: (a) a polyorgano siloxane lubricating oil, and (b) from 10 to wt. percent of a mixture of C to C fatty acid alkaline earth metal salt and a triazine, (c) said triazine melting above about 400 F. and having the formula:

wherein R and R are selected from the group consisting of hydrogen, alkyl, aryl, alkaryl, aralkyl, cyanoalkyl, pyridyl, amino, hydroxy and mercapto radicals and wherein the alkyl radical contains from 1 to 4 carbon atoms and wherein the alkyl portion of the alkaryl and aralkyl radicals contain from 1 to 2 carbon atoms and wherein the alkyl portion of the cyanoalkyl radical contains from 1 to 8 carbon atoms and wherein R and R being unlike when selected from the group consisting of amino, hydroxy and mercapto radicals, and (d) the weight ratio of said triazine to said fatty acid salt in said mixture is from 0.3:1 to 6: 1.

References Cited by the Examiner UNITED STATES PATENTS 2,984,624 5/61 Halter et a1 252-51.5 3,019,187 1/62 Panzer et al 252-40.7 3,086,942 4/ 63 Panzer et a1 252--40.7 3,088,912 5/ 63 Morway et a1 25240.7

DANIEL E. WYMAN, Primary Examiner.

l A A i g 

1. A SOLID LUBRICATING GREASE CONSISTING ESSENTIALLY OF (A) A MAJOR PROPORTION OF A POLYORGANO SILOXANE HAVING A VISCOSITY AT 100*F. OF FROM 10 TO 300 CS., (B) ABOUT 20 TO 40 WT. PERCENT OF A MIXTURE OF 2,4-DIMINO-6-HYDROXY1,3.5-TRIAZINE AND CALCIUM ACETATE IN A WEIGHT RATIO OF FROM 0.7:1 TO 2:1, SAID CALCIUM ACETATE HAVING A PARTICLE SIZE OF LESS THAN ABOUT 2 MICRONS, (C) FROM 1 TO 3 WT. PERCENT OF P,P''-DIOCTYL DIPHENYLAMINE, AND (D) FROM 2 TO 5 WT. PERCENT OF PHENYL-A-NAPHTHYLAMINE. 